Optimization of mechanical and antibacterial properties of Ti-3wt%Cu alloy through cold rolling and annealing

Abstract

In this work, a process of cold rolling with 70% thickness reduction and different annealing temperatures was selected to regulate the microstructure of Ti-3wt%Cu alloy. Microstructural evolution, mechanical properties and antibacterial properties of the Ti-3wt%Cu alloy under different conditions were systematically investigated in terms of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), tensile and antibacterial test. The results indicated that cold rolling could dramatically increase the ultimate tensile stress (UTS) from 520 to 928 MPa, but reduce the fracture strain from 15.3% to 3.8%. With the annealing temperature increasing from 400 to 800 °C for 1 h, the UTS decreased from 744 to 506 MPa and the fracture strain increased from12.7% to 24.4%. Moreover, the antibacterial properties of the Ti-3wt%Cu alloy under different conditions showed excellent antibacterial rate (> 96.69%). The results also indicated that the excellent combination of strength and ductility of the Ti-3wt%Cu alloy with cold rolling and following annealing could be achieved in a trade-off by tuning the size and distribution of Ti2Cu phase, which could increase the applicability of the alloy in clinical practice. More importantly, the antibacterial properties maintained a good stability for the Ti-3wt%Cu alloy under different conditions. The excellent combination of mechanical properties and antibacterial properties could make the Ti-3wt%Cu alloy a good candidate for long-term orthopaedic implant application.